C form of the CAGED chord and scale system
The CAGED chord and scale system is a way to learn scale fingerings from chord shapes. This is very useful as these chord forms are moveable on the fretboard and when you learn the form and the location of the root notes you will have expanded your fretboard knowledge considerably.
This series of diagrams shows the C chord and scale form. Essentially you are forming a C chord, using the shape of the open C chord and utilizing a bar across the the 3 high strings (GBE) to help you move this form up and down the fretboard as a partial bar chord.
When practicing the CAGED system, the important part is learning to recognize the scale patterns that lie within the forms. Some of the CAGED forms are difficult to play but the individual scale tones should be easily accessible if you recognize the general shape of the chord form.
The last couple of diagrams show the C chord form, in the D position. Notice where the root notes are located. You should be able to see that the whole shape just moved up the fretboard. The D root notes are located on the 5th fret of the 5th (A) string and the 3rd fret of the 2nd (B) string. This is the utility of the CAGED form. You are looking at the C form but as you move this form up and down the fretboard, you will be able to find many different scales.
Practice this one.